Are Ceramic-on-ceramic Bearings in Total Hip Arthroplasty Associated With Reduced Revision Risk for Late Dislocation?

Background

Dislocation is a major complication after primary total hip arthroplasty (THA), but little is known about the potential relationships between bearing materials and risk of dislocation. Dislocation within the first year after surgery is typically related to either surgical error or patient inattention to precautions, but the reasons for dislocation after the first year are often unclear, and whether ceramic bearings are associated with an increased or decreased likelihood of late dislocation is controversial.

Questions/purposes

The purpose of this study was to use a national registry to assess whether the choice of bearings–metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), or metal-on-metal (MoM)–is associated with differences in the risk of late dislocation.

Methods

Data from primary THAs were extracted from the New Zealand Joint Registry over a 10-year period. The mean age of patients was 69 years (SD ± 12 years), and 53% were women. The median followup in this population was 7 years (range, 1–13 years). The surgical approach used was posterior in 66% of THAs, lateral in 29%, and anterior in 5%. The primary endpoint was late revision for dislocation with “late” defined as greater than 1 year postoperatively. A total of 73,386 hips were available for analysis: 65% MoP, 17% CoP, 10% CoC, and 7% MoM. In general, patients receiving CoC and MoM bearings were younger compared with patients receiving CoP and MoP bearings.

Results

Four percent of the hips were revised (3130 THAs); 867 THAs were revised for dislocation. Four hundred seventy THAs were revised for dislocation after the first postoperative year. After adjusting for head size, age, and surgical approach, only CoP (hazard ratio [HR], 2.10; p = 0.021) demonstrated a higher proportion of revision, whereas MoP did not (HR, 1.76; 95% p = 0.075). There were no differences of revisions for dislocation in the CoC (HR, 1.60; p = 0.092) and MoM cohorts (HR, 1.54; p = 0.081).

Conclusions

Dislocation is a common reason for revision after THA. The relationships between bearing materials and risk of revision for late dislocation remain controversial. This large registry study demonstrated that bearing surface had little association with the incidence of late dislocation. Future studies with longer followups should continue to investigate this question.

Level of Evidence

Level III, therapeutic study.     

Nine de novo duplications affecting both maternal and paternal chromosomes and an inherited 15q11.2 deletion,in a patient with developmental delay

A patient with developmental delay and nine, de novo, tandem duplications affecting eight different chromosomes that arose on both maternal and paternal chromosomes indicating a vulnerable zygotic or early postzygotic period of development for these errors, potentially affected by genetic and nongenetic factors.     

Association between metabolic syndrome,obesity, diabetes mellitus and oncological outcomes of bladder cancer: A systematic review

Metabolic syndrome is a cluster of several metabolic abnormalities, its prevalence is increasing worldwide. To summarize the most recent evidence regarding the relationship between metabolic syndrome, its components and the oncological outcomes in bladder cancer patients, a National Center for Biotechnology Information PubMed search for relevant articles either published or e‐published up to March 2014 was carried out by combining the following Patient population, Intervention, Comparison, Outcome terms: metabolic syndrome, obesity, body mass index, hyperglycemia, insulin resistance, diabetes, hypertension, dyslipidemia, bladder cancer, risk, mortality, cancer specific survival, disease recurrence and progression. Metabolic syndrome is a complex, highly prevalent disorder, and central obesity, insulin resistance, dyslipidemia and hypertension are its main components. Published findings would suggest that metabolic syndrome per se might be associated with an increased risk of bladder cancer in male patients, but it did not seem to confer a risk of worse prognosis. Considering the primary components of metabolic syndrome (hypertension, obesity and dyslipidemia), available data are uncertain, and it is no possible to reach a conclusion yet on either a direct or an indirect association with bladder cancer risk and prognosis. Only with regard to type 2 diabetes mellitus, available data would suggest a potential negative correlation. However, as the evaluation of bladder cancer risk and prognosis in patients with metabolic disorders is certainly complex, further studies are urgently required to better assess the actual role of these metabolic disorders.     

Assessment of cardiovascular risk in an Italian psychiatric outpatient sample: A chart review of patients treated with second‐generation antipsychotics

Despite the call by the scientific community for a systematic monitoring of physical health in people with psychiatric illnesses, national and international audits have reported poor quality of cardiovascular risk assessments and management in this vulnerable population. Available evidence indicates that in people affected by mental illness, life expectancy is reduced by 10–20 years, mainly due to cardiovascular accidents and metabolic syndrome (MetS)‐related diseases. The primary aim of the present study was to evaluate the accuracy of cardiovascular risk monitoring in an outpatient sample of patients taking second‐generation antipsychotics. The sample consisted of 200 patients consecutively recruited from two community mental health centres. A clinical chart review was performed on the following laboratory tests: total cholesterol, high‐ and low‐density lipoprotein, serum triglycerides, fasting blood glucose, γ‐glutamyl transpeptidase. Blood pressure and waist circumference were measured. A complete cardiovascular risk assessment was available only in 60 patients out of 200 (33.3%). The only variable associated with laboratory tests for MetS was receiving three or more psychotropic medications, which increased fourfold the probability of metabolic screening. In the subsample of patients with full screening, the prevalence of MetS was 33.3%. Our findings suggest that mental health professionals working in community mental health services should incorporate a more systematic assessment of physical health in their practice, and intervene proactively to reduce the significant cardiovascular burden carried by people with several mental illness.     

Ultrafast interface charge transfer dynamics on P3HT/MWCNT nanocomposites probed by resonant Auger spectroscopy

The interfacial electronic structure and charge transfer dynamics of poly-3-hexylthiophene (P3HT) and multi-walled carbon nanotube (Fe-MWCNT) nanocomposites were investigated by near-edge X-ray absorption fine structure (NEXAFS) and resonant Auger (RAS) spectroscopies around the sulfur K-edge. Nanocomposites with 5 wt% (P3HT/Fe-MWCNT-5%) and 10 wt% (P3HT/Fe-MWCNT-10%) of Fe-MWCNT species were prepared and compared with pristine P3HT film. The quantitative NEXAFS analysis shows a strong π–π interchain interaction of the pristine P3HT polymer film, which is reduced by the presence of the Fe-MWCNT. S–KL_2,3L_2,3 RAS spectra were measured at photon energies corresponding to the main electronic transitions appearing in the S–K edge NEXAFS spectrum. Ultrafast charge transfer times were estimated from the RAS spectra using the core-hole clock approach with the S 1s core-hole lifetime as an internal clock. The π–π interchain charge transfer time increases from 4.7 fs on pristine P3HT polymer to 6.5 fs on the P3HT/Fe-MWCNT-5% nanocomposite. The electronic coupling between P3HT and Fe-MWCNT species occurs mainly through the P3HT π* molecular orbital. The increase of Fe-MWCNT concentration from 5 to 10 wt% reduces the charge transfer rate at the resonance maximum due probably to Fe-MWCNT aggregation, reducing the P3HT and Fe-MWCNT electronic coupling.

The electronic coupling between P3HT polymer and multi-walled carbon nanotubes was elucidated using NEXAFS and core hole clock approaches.